This article deals with the functioning of affect and epistemic emotions, such as surprise and curiosity, in self-regulated learning (SRL). The claim is that affect plays a major role in SRL not only as an independent process that can facilitate or impede learning activities and performance but also through its interactions with cognition and metacognition. These interactions render metacognition a hot rather than a cold process. Critical cognitive states that have implications for affect and metacognition are processing fluency/disfluency, interruptions, discrepancies, or gaps in knowledge. Epistemic emotions focus on such cognitive states and are related to metacognitive experiences such as feeling of difficulty (in the case of surprise) and feeling of confidence (in the case of curiosity). Two studies exemplifying the relations between metacognitive experiences and epistemic emotions are presented. The implications of the findings for learning and SRL are discussed.